Induction heating type cooktop having improved usability

ABSTRACT

An induction heating type cooktop includes: a case, a cover plate that is coupled to an upper end of the case and that includes an upper plate arranged to receive a target object, a working coil that is disposed in the case and that is configured to heat the target object, a thermal insulation material disposed on the working coil, and a heating thin film coating that is disposed on a surface of the upper plate of the cover plate or a surface of the thermal insulation material and that has a stacked structure in which an adhesive layer and a heating layer are consecutively stacked.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2020-0020695, filed in Korea on, 19 Feb. 2020, thedisclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to an induction heating type cooktophaving improved usability.

BACKGROUND

Various types of cooking apparatuses are used to heat food at homes orrestaurants. Among the cooking apparatuses, a gas stove can use gas asfuel to heat the food. In recent years, cooking apparatuses, capable ofusing electricity to heat an object to be heated, such as a cookingvessel including a pot, have been widely used instead of the gas stoves.

Methods for heating an object to be heated using electricity can beclassified as a resistance heating method and an induction heatingmethod. In the resistance heating method, an object to be heated isheated by heat that is generated when electric current flows through (i)a metallic resistance wire or (ii) a non-metallic heat generatingelement such as silicon carbide, and the generated heat is delivered tothe object to be heated (e.g., a cooking vessel) through radiation orconduction. In the induction heating method, an object to be heated canbe heated by eddy current that is generated in the object includingmetallic ingredients, by using a magnetic field that is generated arounda coil when a predetermined magnitude of high-frequency power issupplied to the coil.

In recent years, the induction heating method has been applied to mostcooktops.

A cooktop to which the induction heating method is applied can only heata magnetic object. For example, when a non-magnetic object (e.g.,thermal resistant glass, earthenware and the like) is placed on thecooktop, the cooktop cannot heat the object to be heated.

Accordingly, the following methods and cooktops have been developed toovercome limitations of an induction heating type cooktop of the relatedart.

First, a method of adding a heating plate, which can be heated based oninduction heating, between a cooktop and a non-magnetic object has beendevised in order to heat the non-magnetic object. However, for thecooktop with additional heating plate, efficient heating cannot beensured and required time to boil water can be longer than usual.Additionally, a cooking vessel including a magnetic material is heatedin an electro inductive manner using magnetic lines of force that passesthrough the communication hole while the heating plate is heated in anelectro inductive manner using a heating coil. Thus, efficient heatingcannot be ensured.

Second, a conventional cooktop can include a hybrid cooktop that heats anon-magnetic object through a radiant heater to which an electricresistance method is applied and that heats a magnetic object through aworking coil to which an induction heating method is applied. However,for the hybrid cooktop, a high output from the radiant heater andefficient heating cannot be ensured. Additionally, when placing anobject to be heated in a heating area, a user needs to consider amaterial of the object to be heated.

Finally, a conventional cooktop can include an all metal cooktop thatheats all metallic objects to be heated (i.e., a non-magnetic metallicobject and a magnetic metallic object). However, for the all metalcooktop, a non-magnetic non-metallic object to be heated cannot beheated. When a non-magnetic metallic object to be heated is heated, theall metal cooktop is less efficient in heating and incurs more materialcosts than a radiant heater.

SUMMARY

The present disclosure is directed to an induction heating type cooktopthat can heat a target object regardless of a type of the target objectand that can ensure improved heating efficiency.

The present disclosure is also directed to an induction heating typecooktop that can heat both the magnetic object and non-magnetic objectwithout causing a user to consider a material of the target object.

The present disclosure is also directed to an induction heating typecooktop that can heat a target object directly and indirectly using thesame heat source.

The present disclosure is also directed to an induction heating typecooktop in which (i) when a target object has a magnetic property, mostof the eddy current can be supplied to the target object and a workingcoil can directly heat the target object and (ii) when a target objecthas a non-magnetic property, the working coil can indirectly heat theobject to be heated.

The present disclosure is also directed to a heating coating that can beused at a wide range of temperatures and that can ensure excellent andsemi-permanent durability.

The present disclosure is also directed to an induction heating typecooktop in which a component allowing of induction heating can bemanufactured in a simple manner and processing costs can be reduced.

According to one aspect of the subject matter described in thisapplication, an induction heating type cooktop includes a case, a coverplate that is coupled to an upper end of the case and that includes anupper plate arranged to receive a target object, a working coil that isdisposed in the case and that is configured to heat the target object, athermal insulation material disposed on the working coil, and a heatingthin film coating that is disposed on a surface of the upper plate ofthe cover plate or a surface of the thermal insulation material and thathas a stacked structure in which an adhesive layer and a heating layerare consecutively stacked.

Implementations according to this aspect can include one or more of thefollowing features. For example, the heating thin film coating canfurther include a protection layer stacked on a surface of the heatinglayer.

In some examples, the heating thin film coating can be provided by adeposition technique including at least one of sputtering deposition,chemical vapor deposition (CVD), or electron beam deposition. In someexamples, the heating thin film coating can be deposited in a chamberhaving a temperature between 20 to 100° C., the adhesive layer can bedeposited at a deposition speed of 1 to 5 Å/s, the heating layer can bedeposited at a deposition speed of 5 to 15 Å/s, and the protection layercan be deposited at a deposition speed of 1 to 5 Å/s.

In some examples, the heating thin film coating can be provided bythermal processing at 100 to 900° C. for 1 to 5 hours after thedeposition. In some implementations, the heating layer can comprise aplurality of layers.

In some implementations, the adhesive layer can comprise at least one ofmetal or a metal oxide. In some implementations, the heating layer cancomprise at least one of metal or a metal alloy.

In some examples, the protection layer can comprise at least one of aninorganic material or a metal oxide. In some implementations, theadhesive layer can have a thickness between 10 nm to 3000 nm.

In some implementations, the heating layer can have a thickness between0.1 μm to 50 μm. In some examples, the protection layer can have athickness between 0.1 μm to 20 μm.

In some implementations, a skin depth of the heating thin film coatingcan be greater than a thickness of the heating thin film coating. Insome examples, the heating thin film coating can have a resistance valuethat enables the heating thin film coating to be heated by the workingcoil. In some implementations, a diameter of the heating thin filmcoating can be shorter than a diameter of the upper plate of the coverplate.

In some implementations, based on the target object being magnetic,resistance and inductance of the target object can provide an equivalentcircuit with resistance and inductance of the heating thin film coating.In some examples, impedance of the target object can be less thanimpedance of the heating thin film coating in the equivalent circuit. Insome examples, magnitude of eddy current supplied to the target objectcan be greater than magnitude of eddy current supplied to the heatingthin film coating.

In some implementations, based on the target object being non-magnetic,impedance can be present in the heating thin film coating and impedancedoes not present in the target object. In some examples, eddy currentcan be supplied to the heating thin film coating, and eddy current isnot supplied to the target object.

In some implementations, based on the target object being magnetic, thetarget object can be directly heated by the working coil, and based onthe target object being non-magnetic, the target object can be heated bythe heating thin film coating that is heated by the working coil.

In some implementations, the induction heating type cooktop can furtherinclude a blocking plate that is disposed at a lower surface of theworking coil and that is configured to block a magnetic field generateddownward by the working coil, a support member that is disposed betweena lower surface of the blocking plate and a lower surface of the caseand that supports the blocking plate, and a cooling fan that is disposedin the case and that is configured to cool the working coil.

In some examples, the support member can comprise an elastic object forsupporting the blocking plate upward. In some examples, the cooling fancan be configured to (i) suction air from outside of the case anddeliver the suctioned air to the working coil or (ii) suction air in thecase and discharge the suctioned air to outside of the case, and thethermal insulation material can limit delivery of heat to the workingcoil.

The induction heating type cooktop can heat all the magnetic andnon-magnetic objects. Additionally, the induction heating type cooktopcan heat a target object regardless of a position and type of the targetobject. Thus, a user may place and heat a target object in any heatingarea on the upper plate without checking whether the target object has amagnetic or non-magnetic property.

Additionally, the induction heating type cooktop can use the same heatsource to heat a target object directly and indirectly. Accordingly, theinduction heating type cooktop does not require any additional heatingplate or radiant heater. Thus, the induction heating type cooktop canimprove heating efficiency and reduce material costs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an exemplary induction heating typecooktop.

FIG. 2 is a diagram illustrating components included in the inductionheating type cooktop in FIG. 1.

FIGS. 3 and 4 are diagrams illustrating examples of a heating thin filmcoating.

FIGS. 5 and 6 are diagrams illustrating views for describing arelationship between a thickness and a skin depth of a heating module.

FIGS. 7 and 8 are diagrams illustrating views for describing a change inimpedance between a heating thin film coating and a target object basedon the type of the target object.

FIG. 9 is a diagram illustrating an exemplary induction heating typecooktop.

FIG. 10 is a diagram illustrating components included in the inductionheating type cooktop in FIG. 9.

FIG. 11 is a diagram illustrating a view of a state in which targetobjects are placed on the induction heating type cooktop in FIG. 9.

DETAILED DESCRIPTION

FIG. 1 is a diagram illustrating an exemplary induction heating typecooktop 1. FIG. 2 is a diagram illustrating components included in theinduction heating type cooktop 1 in FIG. 1. FIGS. 3 and 4 are diagramsillustrating examples of a heating thin film coating. FIGS. 5 and 6 arediagrams illustrating views for describing features of a skin depthbased on relative permeability of a thin film. FIGS. 7 and 8 arediagrams illustrating views for describing a change in impedance betweena thin film and a target object based on a type of the target object.

Referring to FIG. 1, an induction heating type cooktop 1 can include acase 25, a cover plate 20, working coils WC1 and WC2 (i.e., first andsecond working coils), and heating thin film coatings TL1 and TL2 (i.e.,first and second heating thin film coatings).

The working coils WC1 and WC2 may be installed in the case 25.

In the case 25, various types of devices related to driving the workingcoils WC1 and WC2, in addition to the working coils WC1 and WC2, can beinstalled. The devices, for example, can include a power supplyconfigured to supply AC power, a rectifier configured to rectify ACpower of the power supply into DC power, an inverter configured toconvert DC power, rectified by the rectifier, into resonance current asa result of a switching operation and supply the resonance current tothe working coils, a control module—the control module can include acontrol module for an inverter configured to control a switchingoperation of an inverter and a control module for an input interfaceconfigured to control an input interface—configured to controloperations of various devices in the induction heating type cooktop 1, arelay or a semiconductor switch configured to turn on or turn off theworking coils, and the like.

The cover plate 20 can be coupled to an upper end of the case 25, andcan be provided with an upper plate 15 that allows a target object to beplaced on an upper surface thereof.

For example, the cover plate 20 can include the upper plate 15 forplacing a target object such as a cooking vessel.

The upper plate 15, for example, can be made of a glass material (e.g.,ceramics glass).

The upper plate 15 can be provided with an input interface configured toreceive an input from a user and deliver the input to the controlmodule. In some implementations, the input interface can be disposed atanother position in the induction heating type cooktop 1.

The input interface can be a module for inputting heating intensity or atime period of driving of the induction heating type cooktop 1 andsimilar features desired by the user, and can be implemented in variousdifferent forms such as a physical button or a touch panel and the like.In addition or alternatively, the input interface can be provided with apower button, a lock button, a power level adjustment button (+, −), atimer adjustment button (+, −), a charge mode button and the like.Further, the input interface can deliver an input, received from theuser, to the control module for an input interface, and the controlmodule for an input interface can deliver the input to the controlmodule for an inverter. The control module for an inverter can controlan operation of various devices (e.g., a working coil) based on theinput (i.e., the user's input) received from the control module for aninput interface.

The upper plate 15 can visually display whether the working coil (e.g.,the first working coil and the second working coil WC1 and WC2) isdriving, and heating intensity (i.e., thermal power) of the workingcoil, in a burner shape. The burner shape can be displayed by anindicator including a plurality of light emitting elements (e.g., LEDs)in the case 25.

The first and second working coils WC1 and WC2 can be installed in thecase 25 to heat a target object.

For example, driving of the first and second working coils WC1 and WC2can be controlled by the control module for an inverter, and when atarget object is placed on the upper plate 15, the first and secondworking coils WC1 and WC2 can be driven by the control module for aninverter.

In some implementations, the first and second working coils WC1 and WC2can directly heat a target object (i.e., a magnetic object) having amagnetic property, and first and second heating thin film coatings TL1and TL2 can indirectly heat a target object (i.e., a non-magneticobject) having no magnetic property.

In some implementations, the first and second working coils WC1 and WC2can inductively heat a target object, and can be respectively disposedto overlap the first and second heating thin film coatings TL1 and TL2in a vertical direction (i.e., a perpendicular direction or an up-downdirection).

In FIG. 1, two working coils WC1 and WC2 are installed in the case 25,however, in some implementations, one or three or more working coils canbe installed in the case 25. The first and second working coils WC1 andWC2 installed in the case 25 will be described as an example forconvenience of description.

The heating thin film coatings can include first and second heating thinfilm coatings TL1 and TL2. The heating thin film coating can be providedon any one surface of the upper plate or any one surface of the thermalinsulation material. For example, the heating thin film coating can beprovided on an upper surface or a lower surface of the upper plate, oran upper surface or a lower surface of the thermal insulation material.

In some implementations, the first and second heating thin film coatingsTL1 and TL2 can be disposed on the lower surface of the upper plate 15and spaced apart from each other.

The first and second heating thin film coatings TL1 and TL2 can berespectively disposed to overlap the first and second working coils WC1,WC2 in the vertical direction (i.e., the perpendicular direction or theup-down direction).

In some implementations, the first and second heating thin film coatingsTL1 and TL2 can have at least one of a magnetic property or anon-magnetic property (i.e., a magnetic property, a non-magneticproperty or both of the magnetic and non-magnetic properties).

The heating thin film coating TL1 can have a stacked structure in whichan adhesive layer TLA1 and a heating layer TLH1 are consecutivelystacked, as illustrated in FIG. 3.

The adhesive layer TLA1 can be a component for attaching the upper plateor the thermal insulation material to the heating layer TLH1. Further,the adhesive layer TLA1 can protect the heating layer TLH1 from ionextraction of the upper plate caused by application of a hightemperature for a long period of time and limit deterioration of theperformance of the heating layer TLH1.

The adhesive layer TLA1 can include at least one of metal or a metaloxide to implement the above function. For example, the adhesive layerTLA1 can include a transition metal such as titanium (Ti), chromium(Cr), iron (Fe), nickel (Ni), copper (Cu) and the like, or a metal oxidesuch as aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), and the like.

A thickness of the adhesive layer TLA1 is not limited, but, in someimplementations, the thickness can be 10 nm to 300 nm. When the adhesivelayer TLA1 has a thickness of less than 10 nm, adhesion of the heatinglayer and the upper plate and the like may be reduced, and theperformance of protecting the heating layer may not be sufficientlyensured. When the adhesive layer TLA1 has a thickness of greater than100 nm, the induction heating performance of the heating thin filmcoating TLA1 may deteriorate.

The heating layer TLH1 can be a component allowing the cooktop tooptionally heat a target object.

The heating layer TLH1 can include at least one of metal or a metalalloy to implement the above function. For example, the heating layerTLH1 can include at least one of tin (Sn), cobalt (Co), chromium (Cr),iron (Fe), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), or gold(Au).

A thickness of the heating layer TLH1 is not limited, but, in someimplementations, the thickness of the heating layer TLH1 can be 0.1 μmto 50 μm. When the heating layer TLH1 has a thickness of less than 0.1μm, the function of optional heating may deteriorate. When the heatinglayer TLH1 has a thickness of greater than 50 μm, the heatingperformance itself may deteriorate.

In some implementations, the heating layer THL1 can be formed into aplurality of layers.

Referring to FIG. 4, the heating thin film coating TL1 can furtherinclude a protection layer TLP1. The heating thin film coating TL1 canbe provided on any one surface of the upper plate or the thermalinsulation material, as described above. When the heating thin filmcoating TL1 is provided on the lower surface of the thermal insulationmaterial (between the thermal insulation material and the working coil),the heating thin film coating TLA1 can further include the protectionlayer TLP1 to protect the heating layer from the working coil, forexample. Accordingly, the protection layer TLP1 can be formed on onesurface (a surface opposite to the surface on which the adhesive layerTLA1 is formed) of the heating layer TLH1.

The protection layer TLP1 can include at least one of an inorganicmaterial or a metal oxide to protect the heating layer TLH1. Forexample, the protection layer TLP1 can include at least one of silicondioxide (SiO₂), aluminum oxide (Al₂O₃), cerium oxide (CeO), or magnesiumoxide (MgO).

A thickness of the protection layer TLP1 is not limited, but, in someimplementations, the thickness of the protection layer TLP1 can be 0.1μm to 20 μm. When the protection layer TLP1 has a thickness of less than0.1 μm, the performance of protecting the heating layer may not besufficiently ensured. When the protection layer TLP1 has a thickness ofgreater than 20 μm, the induction heating function of the heating thinfilm coating TLA1 may deteriorate.

The heating thin film coating TL1 can be formed as a result ofdeposition. The method for deposition is not limited. For example, oneof the methods of sputtering deposition, chemical vapor deposition(CVD), and electron beam deposition can be used as the depositionmethod.

When the heating thin film coating TL1 is formed as a result ofdeposition, the thin film that has uniform density entirely can beobtained. Accordingly, the heating thin film coating TL1 formed by usingthe deposition method can ensure more excellent basic performance suchas heating performance and the like than a thin film formed by usinganother method.

In some implementations, the heating thin film coating TL1 can bedeposited in a chamber of 20 to 100° C., preferably, 20 to 40° C. Theadhesive layer TLA1 can be deposited at a deposition speed of 1 to 5Å/s, the heating layer TLH1 can be deposited at a deposition speed of 5to 15 Å/s, and the protection layer TLP1 can be deposited at adeposition speed of 1 to 5 Å/s. Deposition speeds of the abovecomponents can be determined as optimal deposition speeds consideringthe functions and materials of each of the above components. When thedeposition speed is too fast, it is highly likely that a pin hole isformed in the thin film and uniformity of the thin film is reduced. Whenthe deposition speed is too slow, productivity is reduced.

In some implementations, the heating thin film coating TL1 can bethermally processed at 100 to 900° C. for 1 to 5 hours after deposition.

A material for deposition of each component constituting the heatingthin film coating TL1 is described above.

The first and second heating thin film coatings TL1 and TL2 can have athickness to such an extent that the first and second heating thin filmcoatings TL1 and TL2 are inductively heated by the working coils.Description in relation to this is provided below.

A diameter (i.e., a size) of each of the first and second heating thinfilm coatings TL1 and TL2 can be less than a diameter of the upper plate15.

Referring to FIG. 2, the induction heating type cooktop 1 can furtherinclude a thermal insulation material 35, a blocking plate 45, a supportmember 50, and a cooling fan 55.

Since components around the first working coil WC1 are the same as thosearound the second working coil (WC2 in FIG. 1), the components (thefirst heating thin film coating TL1, the thermal insulation material 35,the blocking plate 45, the support member 50 and the cooling fan 55)around the first working coil WC1 will be described below forconvenience of description.

The thermal insulation material 35 can be disposed between the firstheating thin film coating TL1 and the first working coil WC1.

The thermal insulation material 35 can block delivery of heat, which isgenerated while the first heating thin film coating TL1 or a targetobject HO is heated as a result of the driving of the first working coilWC1, to the first working coil WC1.

For example, when the first heating thin film coating TL1 or a targetobject HO is heated based on electromagnetic induction of the firstworking coil WC1, heat of the first heating thin film coating TL1 or thetarget object HO can be delivered to the upper plate 15, and heat of theupper plate 15 can be delivered to the first working coil WC1.Accordingly, the first working coil WC1 may be damaged.

The thermal insulation material 35, as described above, can blockdelivery of heat to the first working coil WC1, limit damage done to thefirst working coil WC1 by heat, and limit deterioration of the heatingperformance of the first working coil WC1.

In some implementations, a spacer can be installed between the firstworking coil WC1 and the thermal insulation material 35.

The spacer can be inserted between the first working coil WC1 and thethermal insulation material 35 such that the first working coil WC1 andthe thermal insulation material 35 do not directly contact each other.Accordingly, the spacer can block delivery of heat, which is generatedwhile the first heating thin film coating TL1 or a target object HO isheated as a result of the driving of the first working coil WC1, to thefirst working coil WC1 through the thermal insulation material 35.

Since the spacer shares a role of the thermal insulation material 35,the thickness of the thermal insulation material 35 can be minimized.Thus, a gap between the target object HO and the first working coil WC1can be minimized.

In some implementations, a plurality of spacers can be provided and canbe spaced apart from each other between the first working coil WC1 andthe thermal insulation material 35. Accordingly, air suctioned into thecase 25 by a cooling fan 55 described below can be guided to the firstworking coil WC1 by the spacer.

For example, the spacer can guide air, suctioned into the case 25 by thecooling fan 55, to the first working coil WC1 to improve coolingefficiency of the first working coil WC1.

The blocking plate 45 can be disposed on a lower surface of the firstworking coil WC1 and can block a magnetic field that is generateddownward when the first working coil WC1 is driven.

For example, the blocking plate 45 can block a magnetic field that isgenerated downward when the first working coil WC1 is driven, and can besupported upward by the support member 50.

The support member 50 can be installed between a lower surface of theblocking plate 45 and a lower surface of the case 25 and can support theblocking plate 45 upward.

The support member 50 can indirectly support the first working coil WC1,the thermal insulation material 35, and the first heating thin filmcoating TL1 upward by supporting the blocking plate 45 upward.Accordingly, a gap between the first working coil WC1 and a targetobject HO can remain constant.

The support member 50, for example, can include an elastic object (e.g.,a spring) for supporting the blocking plate 45 upward. In someimplementations, the induction heating type cooktop 1 may not includethe support member 50.

The cooling fan 55 can be installed in the case 25 to cool the firstworking coil WC1.

For example, driving of the cooling fan 55 can be controlled by theabove-described control module, and the cooling fan 55 can be disposedon a lateral wall of the case 25. In some implementations, the coolingfan 55 can be disposed at another position instead of a lateral wall ofthe case 25. The cooling fan 55 disposed on a lateral wall of the case25 will be described as an example for convenience of description.

The cooling fan 55, as illustrated in FIG. 2, can suction air outsidethe case 25 and deliver the air to the first working coil WC1, or cansuction air (in particular, hot air) in the case 25 and discharge theair out of the case 25.

Thus, components (in particular, the first working coil WC1) in the case25 can be efficiently cooled.

The air outside the case 25, delivered to the first working coil WC1 bythe cooling fan 55, can be guided to the first working coil WC1 by thespacer. Accordingly, the first working coil WC1 can be cooled directlyand efficiently, and durability (i.e., durability as a result ofprevention of damage caused by heat) of the first working coil WC1 canimprove.

The induction heating type cooktop 1 can have the above features andconfigurations. Referring to FIGS. 5 to 8, features and configurationsof the above-described heating module will be described below.

Thickness of each component illustrated in FIGS. 5 and 6 isschematically expressed for convenience of description and does notrelate to an actual scale, and a difference between relative thicknessesof the components do not relate to an actual scale.

FIGS. 5 and 6 are diagrams illustrating views for describing arelationship between thickness and skin depth of a thin film. FIGS. 7and 8 are diagrams illustrating views for describing a change inimpedance between a thin film and a target object based on a type of thetarget object.

The first heating thin film coating TL1 and the second heating thin filmcoating TL2 can have the same technical features. For convenience ofdescription, the first heating thin film coating TL1 will be describedbelow as an example.

The features of the first heating thin film coating TL1 are described asfollows.

The first heating thin film coating TL1 can be made of a material havinga low relative permeability. Types of the material are described above.

For example, the relative permeability of the first heating thin filmcoating TL1 can be low and the skin depth of the first heating thin filmcoating TL1 can be deep. The skin depth can denote a depth to whichelectric current permeates from a surface of a material, and therelative permeability can be inversely proportional to the skin depth.Accordingly, as the relative permeability of the first heating thin filmcoating TL1 becomes low, the skin depth of the first heating thin filmcoating TL1 can become deep.

Additionally, the skin depth of the first heating thin film coating TL1can be greater than the thickness of the first heating thin film coatingTL1. For example, since the first heating thin film coating TL1 has asmall thickness and has a skin depth greater than the thickness thereof,a magnetic field generated by the first working coil WC1 can passthrough the first heating thin film coating TL1 and can be delivered tothe target object HO, such that eddy current is induced to the targetobject HO.

When the skin depth of the first heating thin film coating TL1 is lessthan the thickness of the first heating thin film coating TL1, asillustrated in FIG. 5, a magnetic field generated by the first workingcoil WC1 can hardly reach the target object HO.

When the skin depth of the first heating thin film coating TL1 isgreater than the thickness of the first heating thin film coating TL1,as illustrated in FIG. 6, a magnetic field generated by the firstworking coil WC1 can mostly reach the target object HO. For example,since the skin depth of the first heating thin film coating TL1 isgreater than the thickness of the first heating thin film coating TL1, amagnetic field generated by the first working coil WC1 can pass throughthe first heating thin film coating TL1 and can be mostly used by thetarget object HO. Thus, the target object HO can be mainly heated.

The first heating thin film coating TL1 can have a small thickness asdescribed above. Accordingly, the first heating thin film coating TL1can have a resistance value to the extent that the first heating thinfilm coating TL1 can be heated by the first working coil WC1.

The thickness of the first heating thin film coating TL1 can beinversely proportional to the resistance value (i.e., a surfaceresistance value) of the first heating module HM1. For example, as thethickness of the first heating thin film coating TL1 becomes small, theresistance value (i.e., a surface resistance value) of the first heatingthin film coating TL1 can become high.

Since the first heating thin film coating TL1 having the above featuresis provided to heat a non-magnetic object, an impedance feature betweenthe first heating thin film coating TL1 and the target object HO canvary depending on whether the target object HO disposed on the uppersurface of the upper plate 15 has a magnetic or non-magnetic property.

A case in which the target object has a magnetic property is describedbelow.

Referring to FIGS. 4 and 7, when a magnetic target object HO is placedon the upper surface of the upper plate 15 and the first working coilWC1 is driven, resistance R1 and inductance L1 of the magnetic object HOcan form an equivalent circuit along with resistance R2 and inductanceL2 of the first heating module HM1.

In some implementations, impedance (i.e., impedance including R1 and L1)of the magnetic target object can be less than impedance (i.e.,impedance including R2 and L2) of the first heating thin film coatingTL1, in the equivalent circuit.

When the above equivalent circuit is formed, magnitude of eddy currentI1 supplied to the magnetic target object HO can be greater thanmagnitude of eddy current I2 supplied to the first thin film TL1.Accordingly, most of the eddy current can be supplied to the targetobject HO such that the target object heated HO is heated.

For example, when a target object HO has a magnetic property, the aboveequivalent circuit can be formed, and most of the eddy current can besupplied to the target object HO. Thus, the first working coil WC1 candirectly heat the target object HO.

In some implementations, since some of the eddy current can be suppliedto the first heating thin film coating TL1, the first heating thin filmcoating TL1 can be slightly heated. Accordingly, the target object HOcan be indirectly and slightly heated by the first heating thin filmcoating TL1. However, a degree to which the target object HO isindirectly heated by the first heating thin film coating TL1 can be lessmeaningful than a degree to which the target object HO is directlyheated by the first working coil WC1.

A case in which the target object has a non-magnetic property isdescribed below.

Referring to FIGS. 4 and 8, when a non-magnetic target object HO isplaced on the upper surface of the upper plate 15 and the first workingcoil WC1 is driven, impedance may not be present in the non-magnetictarget object HO, and impedance may be present in the first heating thinfilm coating TL1. For example, resistance R and inductance L can bepresent only in the first heating thin film coating TL1.

Accordingly, eddy current I can be supplied only to the first heatingthin film coating TL1 but not to the non-magnetic target object HO. Forexample, eddy current I can be supplied only to the first heating thinfilm coating TL1 such that the first heating thin film coating TL1 isheated.

In some implementations, when the target object HO has a non-magneticproperty, eddy current I can be supplied to the first heating thin filmcoating TL1 to heat the first heating thin film coating TL1, and thenon-magnetic target object HO can be indirectly heated by the firstheating thin film coating TL1 heated by the first working coil WC1, asdescribed above.

A protection temperature of the upper plate 15 can be preset by amanufacturer of an upper plate or a manufacturer of a cooktop. Forexample, a manufacturer of an upper plate may deliver informationregarding a temperature-based lifespan of the upper plate to amanufacturer of a cooktop, and the manufacturer of a cooktop maycalculate a lifespan of a product/the cooktop considering a length oftime for which the cooktop is used and may set a protection temperatureof the upper plate 15.

Further, a temperature sensor can be installed in one area of the upperplate 15, which can sense a change in temperatures of the upper plate 15and supply information regarding the sensed temperature to theabove-described control module.

As such, regardless of whether the target object HO has a magnetic ornon-magnetic property, the target object HO can be heated directly andindirectly by a single heat source referred to as the first working coilWC1. For example, when the target object HO has a magnetic property, thefirst working coil WC1 can directly heat the target object HO, and whenthe target object HO has a non-magnetic property, the first heating thinfilm coating TL1 heated by the first working coil WC1 can indirectlyheat the target object HO.

The induction heating type cooktop 1, as described above, can heat allthe magnetic and non-magnetic objects. Accordingly, the inductionheating type cooktop 1 can heat a target object regardless of theposition and type of the target object. Thus, a user may place a targetobject in any heating area on the upper plate without checking whetherthe target object has a magnetic or non-magnetic property, and improvedusability can be ensured.

Additionally, the induction heating type cooktop 1 can use the same heatsource to heat a target object directly and indirectly. Accordingly, theinduction heating type cooktop 1 does not require any additional heatingplate or radiant heater. Thus, the induction heating type cooktop 1 canimprove heating efficiency and reduce material costs.

Another exemplary induction heating type cooktop is described below.

FIG. 9 is a diagram illustrating an exemplary induction heating typecooktop 2. FIG. 10 is a diagram illustrating components included in theinduction heating type cooktop 2 in FIG. 9. FIG. 11 is a diagramillustrating a state in which target objects are placed on the inductionheating type cooktop 2 in FIG. 9.

The induction heating type cooktop 2 can be similar to the inductionheating type cooktop 1 in FIG. 1 except for some components and effects,thus the differences will be described below.

Referring to FIGS. 9 and 10, the induction heating type cooktop 2 can bea zone free type cooktop unlike the induction heating type cooktop 1 inFIG. 1.

The induction heating type cooktop 2 can include a case 25, a coverplate 20, a plurality of heating thin film coatings TLG, a thermalinsulation material 35, a plurality of working coils WCG, a blockingplate 45, a support member 50, a cooling fan, a spacer, and a controlmodule.

The plurality of heating thin film coatings TLG can overlap theplurality of working coils WCG in the vertical direction and can bedisposed to respectively correspond to the plurality of working coilsWCG on a one-to-one basis.

In some implementations, the plurality of heating thin film coatings TLGcan correspond to the plurality of working coils WCG on a one-to-manybasis instead of a one-to-one basis. The plurality of heating thin filmcoatings TLG disposed to correspond to the plurality of working coilsWCG on a one-to-one basis is described as an example for convenience ofdescription.

The induction heating type cooktop 2 can be a zone free type cooktopincluding the plurality of heating thin film coatings TLG and theplurality of working coils WCG. Accordingly, the cooktop 2 can heat asingle target object HO using some or all of the plurality of workingcoils WCG or some or all of the plurality of heating thin film coatingsTLG at the same time. In some implementations, the cooktop 2 can heat atarget object HO using some or all of the plurality of working coils WCGand some or all of the plurality of heating thin film coatings TLG.

Thus, as illustrated in FIG. 9, target objects HO1 and HO2 can be heatedin an area (e.g., the upper plate 15 area) where the plurality ofworking coils (WCG in FIG. 8) and the plurality of heating thin filmcoatings TLG are provided, regardless of the positions, sizes and typesof the target objects HO1 and HO2.

What is claimed is:
 1. An induction heating type cooktop, comprising: acase; a cover plate that is coupled to an upper end of the case and thatincludes an upper plate arranged to receive a target object; a workingcoil that is disposed in the case and that is configured to heat thetarget object; a thermal insulation material disposed on the workingcoil; and a heating thin film coating that is disposed on a surface ofthe upper plate of the cover plate or a surface of the thermalinsulation material and that has a stacked structure in which anadhesive layer and a heating layer are consecutively stacked.
 2. Theinduction heating type cooktop of claim 1, wherein the heating thin filmcoating further comprises: a protection layer stacked on a surface ofthe heating layer.
 3. The induction heating type cooktop of claim 2,wherein the heating thin film coating is provided by a depositiontechnique including at least one of sputtering deposition, chemicalvapor deposition (CVD), or electron beam deposition.
 4. The inductionheating type cooktop of claim 3, wherein: the heating thin film coatingis deposited in a chamber having a temperature between 20 to 100° C.,the adhesive layer is deposited at a deposition speed of 1 to 5 □/s, theheating layer is deposited at a deposition speed of 5 to 15 □/s, and theprotection layer is deposited at a deposition speed of 1 to 5 □/s. 5.The induction heating type cooktop of claim 3, wherein the heating thinfilm coating is provided by thermal processing at 100 to 900° C. for 1to 5 hours after the deposition.
 6. The induction heating type cooktopof claim 1, wherein the heating layer comprises a plurality of layers.7. The induction heating type cooktop of claim 1, wherein the adhesivelayer comprises at least one of metal or a metal oxide.
 8. The inductionheating type cooktop of claim 1, wherein the heating layer comprises atleast one of metal or a metal alloy.
 9. The induction heating typecooktop of claim 2, wherein the protection layer comprises at least oneof an inorganic material or a metal oxide.
 10. The induction heatingtype cooktop of claim 1, wherein the adhesive layer has a thicknessbetween 10 nm to 3000 nm.
 11. The induction heating type cooktop ofclaim 1, wherein the heating layer has a thickness between 0.1 μm to 50μm.
 12. The induction heating type cooktop of claim 2, wherein theprotection layer has a thickness between 0.1 μm to 20 μm.
 13. Theinduction heating type cooktop of claim 1, wherein a skin depth of theheating thin film coating is greater than a thickness of the heatingthin film coating.
 14. The induction heating type cooktop of claim 1,wherein the heating thin film coating has a resistance value thatenables the heating thin film coating to be heated by the working coil.15. The induction heating type cooktop of claim 1, wherein a diameter ofthe heating thin film coating is shorter than a diameter of the upperplate of the cover plate.
 16. The induction heating type cooktop ofclaim 1, wherein, based on the target object being magnetic, resistanceand inductance of the target object provide an equivalent circuit withresistance and inductance of the heating thin film coating.
 17. Theinduction heating type cooktop of claim 16, wherein impedance of thetarget object is less than impedance of the heating thin film coating inthe equivalent circuit.
 18. The induction heating type cooktop of claim17, wherein magnitude of eddy current supplied to the target object isgreater than magnitude of eddy current supplied to the heating thin filmcoating.
 19. The induction heating type cooktop of claim 1, whereinbased on the target object being non-magnetic, impedance is present inthe heating thin film coating and impedance is not present in the targetobject.
 20. The induction heating type cooktop of claim 19, wherein eddycurrent is supplied to the heating thin film coating, and eddy currentis not supplied to the target object.
 21. The induction heating typecooktop of claim 1, wherein, based on the target object being magnetic,the target object is directly heated by the working coil, and wherein,based on the target object being non-magnetic, the target object isheated by the heating thin film coating that is heated by the workingcoil.
 22. The induction heating type cooktop of claim 1, furthercomprising: a blocking plate that is disposed at a lower surface of theworking coil and that is configured to block a magnetic field generateddownward by the working coil; a support member that is disposed betweena lower surface of the blocking plate and a lower surface of the caseand that supports the blocking plate; and a cooling fan that is disposedin the case and that is configured to cool the working coil.
 23. Theinduction heating type cooktop of claim 22, wherein the support membercomprises an elastic object for supporting the blocking plate upward.24. The induction heating type cooktop of claim 22, wherein the coolingfan is configured to (i) suction air from outside of the case anddeliver the suctioned air to the working coil or (ii) suction air in thecase and discharge the suctioned air to outside of the case, and whereinthe thermal insulation material limits delivery of heat to the workingcoil.